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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: James Bottomley <jejb@linux.ibm.com>
Cc: linux-integrity@vger.kernel.org, Peter Huewe <peterhuewe@gmx.de>,
	Jason Gunthorpe <jgg@ziepe.ca>, Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 1/2] tpm: Use GFP_KERNEL for allocating struct tpm_buf
Date: Wed, 9 Oct 2019 01:52:02 +0300	[thread overview]
Message-ID: <20191008225202.GA12089@linux.intel.com> (raw)
In-Reply-To: <1570475528.4242.2.camel@linux.ibm.com>

On Mon, Oct 07, 2019 at 12:12:08PM -0700, James Bottomley wrote:
> From: James Bottomley <James.Bottomley@HansenPartnership.com>
> Subject: [PATCH] tpm: use GFP kernel for tpm_buf allocations
> 
> The current code uses GFP_HIGHMEM, which is wrong because GFP_HIGHMEM
> (on 32 bit systems) is memory ordinarily inaccessible to the kernel
> and should only be used for allocations affecting userspace.  In order
> to make highmem visible to the kernel on 32 bit it has to be kmapped,
> which consumes valuable entries in the kmap region.  Since the tpm_buf
> is only ever used in the kernel, switch to using a GFP_KERNEL
> allocation so as not to waste kmap space on 32 bits.
> 
> Fixes: a74f8b36352e (tpm: introduce tpm_buf)
> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

Thanks a lot. Makes a lot more sense than the patch that I sent.

Reviewed-by:  Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

  parent reply	other threads:[~2019-10-08 22:52 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-03 18:51 [PATCH v3 0/2] tpm: Detach page allocation from tpm_buf Jarkko Sakkinen
2019-10-03 18:51 ` [PATCH v3 1/2] tpm: Use GFP_KERNEL for allocating struct tpm_buf Jarkko Sakkinen
2019-10-04  0:25   ` James Bottomley
2019-10-06 10:03     ` Jarkko Sakkinen
2019-10-07 19:12       ` James Bottomley
2019-10-07 23:43         ` Jerry Snitselaar
2019-10-08 22:52         ` Jarkko Sakkinen [this message]
2019-10-09 21:36         ` Jarkko Sakkinen
2019-10-11 16:03           ` James Bottomley
2019-10-03 18:51 ` [PATCH v3 2/2] tpm: Detach page allocation from tpm_buf Jarkko Sakkinen
2019-10-04 16:37   ` James Bottomley
2019-10-04 17:37     ` Mimi Zohar
2019-10-04 17:41       ` James Bottomley
2019-10-04 18:24         ` Jerry Snitselaar
2019-10-06 23:32           ` Jarkko Sakkinen
2019-10-04 19:01     ` Jarkko Sakkinen

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